Adjustable support



Aug. 26, 1952 L. BOLTUCH 2,603,357

ADJUSTABLE SUPPORT Filed April 26, 1950 s Sheets-Sheet 1 E I w r: A [6 .5 4d

INVENTOR learzfializzo 5f ATTORNEY Aug. 26, 1952 BOLTUCH 2,608,367

ADJUSTABLE SUPPORT Filed April 26, 1950 3 Sheets-Sheet 2 I 22 [e012 floliwfi,

Z/ /7 BY [2 a 144% /fi amp ATTORNEY R Y m w W 5 N) 3 t w O s mu m 0 a qr. Z 2 t e Z m s s a m 9 mm Li Y u B. T mm m Lw D A Aug. 26, 1952 Flled Aprll 26 1950 Patented Aug. 26 1952 OFFICE" -ADJUSTABLE SUPPORT Leon Boltuch, Bronx, N. 1 i Application April 26, 1950, Serial No. 158.311

15 Claims. 1 l I J The present invention relates generally .to .an adjustable bracket of the type whichpennits -of adjusting the positionpi the load carried by the bracket tosubstantially any point .within a sphere whose diameter isdefined by the lon est dimension of the'bracket. .More particularly, the present invention relates to this type of adjustable bracket which is designed to support a relatively light load whichis best illustrated in the present application by a desk lamp.. It will be understood that while the invention is illustrated herein as embodied. inadesk lamp in which an illuminating unit, whether in the form of a conventional electric bulb. or in the form, of a tubular discharge lamptcgether with a shade or reflector therefor, constitutes the load, the invention may be. employed in. adjustably supporting a variety of loads. Itwill, therefore, be understood that wherever the'present specification speaks of a lamp, or a desk lamp,.or a table a p, an illuminating unit, the language is merely illustrative and is intended to include a variety ofothertypes of loads whether they be in the form of handtools or electrically driven tools or other such devices.

. Essentially the present invention contemplates a base, a bracket carried by the base, and a load carried by the free end of -the bracket; the bracket -having-a universal movement with reference to the base thus permitting for the adjustmentoi the position of the load unit in any position desired with reference to the base.

2 One of the'objects of the present invention is to provide in an organization of the type described means which firmly maintain the load 9 unit in its adjusted position, while at the same time the means operates to permit movement of the load unit with great facility from the adjusted position ofany other desired position.

Another object of the invention is that the means which servesito maintain the load unit in its adjusted position also operates to assist in the'movement of the load unit oncethe movein'ent is 'set into operation. p A still further object of the fprovide counterbalancing means which serve to "counterbalance the'leverage of the load unit in selected position without imposing any fricti'onaI burdens upon the piv'otal connections of the parts'involved.

Inthe' specific embodiment of the present in- "vention' shown herein, the bracket is jointed and i? is" universally mounted on' theba'se. "It is the aim of the present invention to provide counterbalancing means for the leverage of the load unit invention is to,

- joint between the twoarms ofwthe' bracket .nor

upon the universal pivotof thebrackefiupon the base. 1.). 13.

. Another object of the present invention i's to provide the cooperation of friction and a spring for counterbalancing the load in any selected position, without subjecting the joints or pivots of. the bracket to any undue stresses;

ULHaving. thusdescribed the general objects of the present invention, reference is now had toithe following. specification and the accompanying drawingsfora full and clear disclosure aofsall the details thereoflit being understood thatthe'se aremerely illustrative and that variations thereof falling within the scope of the appending claims will be apparent to persons skilled'in: the ar.

.In the drawings:

1 is a side view of a preferred embodiment of the invention. Fig. 2'is a side view of the base and lower arm.

Fig. 3is an enlarged sectional view or the 'base and lower arm. I

Fig. 4 is a view taken on line 4-4 in Fig. 3. Fig. 5 is a'v'iew on line 55 in Fig. 3. l Fig. 6 is'aview on line 6-45 in Fig. 3. i

. Fig. '7 is'a side view of one half of the'housirig.

. Fig. 8 is a view on line 8-8 in Fig. 3.

Fig. 9 is a sectional view of one of the joints. Fig. 10 is a view on line l -l0 in Fig. 9. Fig. 11 is a view on line ll--l| in Fig. 9.

' Fig. 12 is a view on line l2--I2 in Fig. 1; l l

Fig. 13 isa perspective view of one of the tubular arms.

Figs. 14 tol'l, inclusive, illustrate the critical positions of the load unit.

a lamp unit or the like, universally mounted on the free. end of the bracket. l 1

An important phase of the present invention resides in providing within the bracket devices .Which operate to exertlthe desired force to support and counterbalance the bracket and lamp unit in anydesired position, the sameforce also serving to assistina movement of, the lamp" unit from one adjustedposition toanother; the essential characteristictof the organization being that the operating force does not involve the .umversn mountings nor the joint between the arms ofthe bracket with the consequence. that thelampiunit is supported in airee floating manner and-the hfe'ofithe aparatus is lengthened. :ii: 31;

Essentially, the present invention employs for this purpose a slidable friction element and a resilient power storage element both disposed within the tubular arms. These elements are merged into a single force by means of a linkage which is connected to the friction element and by-passes the resilient power storage element and the adjacent joint. The friction element takes the form of an elongated split resilient friction sleeve dis'posed within the tubular arms of the bracket. The resilient power storage element is in the form of a helical spring disposed within each of the tubular arms and pressing against =spring into a single effective force which provides 1a virtually floating support for the lamp unit; and

which. also serves to retain the lamp unit in any adjusted position.

: :Wlth the above general statement of the principles involved in the present invention, we may now. turn to a description of a preferred and specific embodiment.- I

In the drawings 12 illustrates a lamp housing which in the present case is of the type which 'houses a. pair of luminescent discharge/tubes. V The lamp unit [2 is carried by a pair of jointed arms I3 and Id pivoted to each other at IS. The :inner arm M is universally mounted on the base [6. Thus, by means of this organization, the

lamp unit 12 may occupy substantially any posixtion within the sphere haVing the overall length of the arms [3 and M as its diameter. Thus the lamp unit [2 may be moved with the outer arm l3 about the pivot ['5 to a position in which the lamp unit illuminates the area-closely adjacent to the base 16. This isillustrated by the dotted lineposition A of the outer arm 13.

If desired, with the arms [3 and [4 in substantial alignment the varm M may be extended as indicated by the dotted line position 13, thus providing illumination of an area far removed from the base. It. In addition, the lamp unit 12 swings vertically about the pivot I l and also swings laterally about the line I8. Thus the lamp unit has a universal movement about the free end :of the bracket and also has universal movement about the base it.

The universal pivotal mountin of the inner bracket arm Id upon the base It comprises several cooperating elements. One of these ele-.

,ments is a stud having an enlarged circular base 2| with a pair of diametrically opposed and interiorly threaded passages 22 to receive the screws 24 for mounting the stud on the base It as shown in Fig. 1. The base It may be of any suitable shape, but is preferably substantially hollow so as to provide for mountingtherein transformers or ballast units or switches and other such devices as are associated with a lamp unit of the type described. This base it. pro" vides a table-like plate ll to receive .the. stud 2!]. The table plate H is provided with an aperture which registers with the axial passage 25 in the -rstud 20 toprovidea passage for electric cord through the. bracket. The stud Zil is provided-1 with an annular channel 26' as shown. The

, channelZB receives a lug from the two-part hous- Hing 281whichis mounted .upon the studze and firmly secured thereon. The two-part housing 28 thus may rotate aboutithe stud 20. 'It is de-" sired, however, to limit the rotation around the stud 2c in order to minimize the possibility of injuring the electric cord which passes through the bracket. For this purpose, therefore, the channel 25 does not extend throughout the 360 but is provided with an interruptionv which serves as a shoulder to limit the rotational movement of the housing 28 upon the stud. The upper half of the stud 2c is preferably offrusto conical shape as shown and is designed to-fit snugly within the housing 28 which has a corresponding interior surface as resting upon frusto conical surface of the stud so as to provide firm support for the housing and bracket and still permit the lamp unit and bracket to rotate about a vertical axis.

: The two-part housing 28 consists of two complementary halves which may be die cast. In their lower portions the two parts of the housing are each semi-annular and have dove-tailing or inter-engaging portions 38 and 21. These lowerportions of the two halves of thehous-ing, therefore, form a solid annulus about theintermediate portion of the stud 28. One of thehalves rhas .a lu 3! projecting inwardly which :enters the channel 26; The complementary dove-tailing or inter-engaging portions are provided with passages which together ,form a pair of continuous passages. 32; Inj'the assembly ofthe present device, the two parts of the housing 28 are placed in an embracing position around the stud 2E! and adjusted to a position where the passages 32 register with thepassages 22in the :stud. Pins or pintles 33 are then driven into :the passages 32 and' serve to unite the two halves of the housing firmly and solidly around :the stud 20 while at the same time permitting of rotation of the housing around the stud 2,0, the lug 531 servin to engagLthe stop in the channel 26 and thereby limit this rotational movement.

Theupper portion of the housing 28 comprises a pair of dished plates 34 which have inwardly directed annular flanges 35. Each half of; the

"housing also has a curved arm 35 each havin notch at its free end-as shown. The hinge unit ll) consists of an annular portion at and a tubular extension 42 integral therewith. The passages in the parts 4] and 42 are in communication and form a continuous, passage for the electric cord. The ends-of the ring 4| arerabbeted as shown at 43 for seating the same on the flanges 35 in the corresponding halves of the housing 28. 7

It will now be understood that the universal pivot consists of the stud 28, the two-part housing 28, and the hinge unit 40.

' then receive. the pins or pintles 33 thereby firmly assembling these several parts. together and permitting of rotation about a verticalaxis of the housing with reference to the studand of rotation about the horizontal axis :of the hinge unit.

After this assembly is;completed,-the clips 46 are inserted as shown" in order to hold the upper part of the housing in firm assembled relation.

vment with reference to the stud 20 and the base |6 upon which it'is mounted.

The ring 4| is provided with an opening which permits the electric cord to enter through the passage 25 in the stud, the cord also entering from the ring 4| into the tubular portion 42 and into the tube l4. The wall of the tubular portion 42 is preferably provided with a pair of opposite and inwardly projecting thick stops 45. The stops 45 serve asrests for tubular arm l4. The tubular bracket [4 fits snugly and firmly within the tube 42 and is provided at its end with a pair of bottom slots 62 which slide over the lugs 45, and the tube or arm I4 is thereby maintained firmly in position and against rotation.

Disposed within the tubular bracket arm I4 is an elongated resilient split sleeve made of spring steel. This sleeve presses resiliently and firmly against the inner face of the tubular arm l4 and exerts considerable friction.- The finger 52 integral with the sleeve 5| projects laterally from the tube through an elongated slot 53.

The coil spring 50 is disposed within the tube I4 between the sleeve 5| and the lugs 45 at the lower end of the tube l4. If desired, an annulus I 54 maybe interposed between the upper end of the spring 59 and the lower end of the resilient rivet 58. The inner face of the slider 56 is provided with a groove 59. The link BB is made of a metal rod bent into the shape as shown; therei by providing one loop which enters the notch -31 in the arm 36 of the housing 28 and another loop at-the end which enters the notch 59 in the slider 56. i The link 60 thus serves to position the resilient sleeve 5| and to hold the spring 50 in a compressed condition. 1

The counterbalancing force provided by the organizationthus' far described comprises a fixed frictional force and a variable resilient pres- -sure. The resilient pressure increases with the departure of the bracket arm from the vertical,

l. and this increased force'is available as the moment of the load grows. The. same resilient pressure operates. to move the friction sleeve and bracket arm when the load is being guided I manuallyfrom one position to another.

Thus as the arm [4 is moved from the vertical posi .tion to the horizontal position a constantlyincreasing active resilientgpressure of spring 50 is added to the fixed frictional resistance. of the sleeve 5| to producethe necessary force for counterbalancing the moment of the load. This is caused by the transmission of the movement of the arm 14 .to the sleeve 5| through the link l 69 and the resultant compression of the helical spring-45o; n

Having described the manner in which the, arm I4 is universally mounted on the base 16,

the following portion of the specificationdescribes the structure of the joint 15 between the upper end of the inner bracket arm. I4 and the lower end of the outer bracket arm [3. The

joint t5 consists of a two-part housing 54 and .a hinge ring 65 which is embraced by the housing and rotates within the housing 64 about are horizontal axis. The housing 64 comprises a teriorly directed annular flanges 10.

' 6 receives the upper end of the inner bracket'arm M. The housing has a pair of inwardly directed lugs 61 which are received by correspondingslots 68 in the upper endof the tube M. The tubular portion 66 curves as shown and carries at the upper end a pair of plates 69 which have in- The housing also has the arm 1| which is provided with a notch I2 as shown. The two parts of the housing are held together by assembly clips 13.

The hinge ring 65 comprises the annularportion 15 which is rabbeted on each face at 16 and an outwardly extending tubular portion 11. The ring portion 15 is embraced by the two halves of the housing with the ring 15 rotatably mounted on the flanges 10. The tube TI receives the tubular bracket or arm l3 and is provided with a pair of integral lugs 19 which are receivedby bottom slots in the arm l3 to prevent rotation of the arm. The portion 15 has an opening as shown for the passage of the electric wire.

It will now be understood that when these several units are assembled together, the tube 66 of the housing 64 becomes fixed with the tube I4, and the tube l3 becomes fixed with the tube 11, and by means of the rotary engagement between the ring 15 and the housing 64 the bracket arm I3 is jointed to the bracket arm I4 and is pivoted thereto about a horizontal axis.

It is preferred that the arms [3 and I4 should move in the same plane as shown. Like the arm M as previously described, the arm I3 is similarly provided with a coil spring 59 and the resilient friction sleeve 5|, which are operated on by the link 69 carried by the notch 12 in the housing 54 and the notch 59 in the slider 56 which is aifixed to the projected finger 52.-

. said plates.

The coil spring 59 and resilient friction sleeve 5| in the upper bracket arm I3 cooperate with each other and with the link 50 as previously described and serve to counterbalance the leverage of thelamp unit 2 about the joint -|5.

The upper end of the arm I3 is jointed to the lamp unit I2 by means of a universal mounting which in its essential respects is identical with the universal mounting interposed between the arm I4 and the base l6. It'comprisesa stud 29 as previously described and a two-part housing 89 which embraces the stud 20 inthe same manner as the housing 28 and cooperates therewith in the same manner and thus provides for rotation of the stud 20' withinthe housing 80. At its outer end, however, the housing is provided with the rabbeted annular ring 8| which is received and embraced by the plates 82 with the rabbeted portion riding on and rotatable on the interior flanges 83 on The plates 82 are carried by the tubular element 84 which receives the free end of the tube l3. The stud'20is mounted on lamp unit l2. Thus lamp unit. I2, together with the stud 20, may be rotated within the housing .80- and similarly the lamp unit ll together with the housingBD, may berotated between the plates 82 about another axis. In addition, itis desirable also to provide rotation for tube 84 on tube l3 so that the load unit l2 with the intermediate elements 20, 89 and 84 should be'free to rotate on the tube l3, to an extent short of 360. For this purpose the tube 84 has an annular inner channel 85 which does not extend around the full circle, and tube I3 is provided'witha lug 86 thatrides in the channel 85 and is downwardly extending tubular portiontfi whichfls s pp d at t s oi e h nn 1: 3

,sity for friction at the pivoted joints. sleeves with the helical springs 55} may be disposed within a tubular arm which may have much greater range of movement. ever, preferred to provide the upper arm with a range of movement that approximates ninety balancing of the load in all positions. purpose the friction sleeve in the upper arm "ismade to offer greater frictional resistance than it will now be :seen'that the present organiza- .:tio'n.provides adesk lamp in which the illumiuiating unit may .be moved so as to provide desired illumination over any portion of a large illuminating unit .is universally movable with reference to the bracket and the bracket and illuminating unit together constitute an organi- .zation whichis universally movable with reference to the. base. In addition, the jointed bracket with the counterbalancing devices carried interiorly of the brackets serve to maintain the illuminating unit in any adjusted position and permit of the ready movement of the unit to any desired position. This .is all accomplished without imposing any undue strains upon the several joints and pivots in the bracket and support.

The resilient internal friction sleeves 5] are long lasting and operate to eliminate the neces- These an internal diameter less than a half inch, thus permitting the use of slender and attractive tubular arms.

In operation only a slight manual pressure on the lamp overcomes the internal pressure of the sleeves BI, and in eiiect the operator needs only to direct the lamp to the desired position, the work of moving the lamp being provided by the springs.

The helical. springs 59 exert their pressures axially of the tube and in line with the pivotal joints Thus these springs do not exert directly any moment or leverage about any pivot or joint. On the other hand these springs exert considerable pressures against the 5|. These pressures, together with the frictional resistance of the sleeves, serve to overcome the moments of the load or illuminating unit about the pivotal joints, oppose the downward movement of the load and retain it in any adjusted position. On the other hand when the user applies but slight directive manual pressure to ;the load unit in any direction, the leverage of this manual pressure about either joint is substantial and the frictional resistance of the sleeve 5 l is readily overcome.

With the lamp unit resting on a working desk,

the arm it has a range of travel not in excess of ninety degrees from the vertical.

The arm l3, the upper arm, could if desired be given a It is, howdegrees. For this purpose, the tubular portion .64 is curved as shown and, as a consequence,

the movement of arm 13 is limited to the range between the full and dotted line positions in Fig. '1;

The forces in the present organization are distributed to provide for the proper counter-' For this the friction sleeve in the lower arm as by its heavier stock.

The manner in which the forces operate to maintain the lamp or other load unit in adjusted position will be best understood by reference to the diagrams in Figs. 14, 15, 16, and '17, which are specifically applicable to the specific friction sleeves friction sleeve in this position may bev spoken of as supplying excess friction. The upper joint spring in thisposition Supplies very little counterbalancing moment and upper friction sleeve supplies substantially the pressure needed to prevent the load unit from moving downwardly about the joint I5.

In Fig. 15, the lower joint friction sleeve supplies the needed friction acting against the :lower joint spring and prevents :it from raising the lower, arm by its excess counter-balancing moment. In the upper arm the same situation exists, for here too, the spring is compressed so as to supply an excess counterbalancing moment which is balanced by the friction sleeve. Thus it is that in the position shown in Fig. 15 the ,springs exert their maximum moments which are partly counterbalanced by the friction.

Thus the lower arm spring is strong enough to counterbalance the moment of the load'in Fig. 14, where the loadexerts its greatest moment. In Fig. .15, the lower arm spring remains in the same degree of compression but the load moment is considerably reduced. So in this position the lower friction sleeve counterbalances theexcess pressure or moment of the lower spring.

In Fig. .16 the lower arm spring supplies almost Zero counterbalancing moment. 7 In this position therefore, the lower friction sleeve supplies the entire ,counterbalancing moment to keep the lower arm vertical. The upper arm spring supplies most of the necessary moment to keepthe, upper arm in horizontal position and the upper friction sleeve shares, the load and also supplies excess friction. t 7

What was said about the. lower spr n a sleeve in the discussion of ,Fig. lfiisalso applicable to Fig. 1'7. In this position the upperjoint spring supplies excess counterbalancin moment which tends to move theupper armto dotted line position. The upper friction sleeve supplies the frictional force to counteract the spring. to hold the arm in the full lineposition.

Figs. 14 to 17 show the arms in critical positions. The other positions which are intermediate the positions shown involve thecombinations .of forces to maintain the load in adjusted position and to facilitate the movement of the load from fhelical spring.

The moment of the load about'joint' [:5 .decreases as the upper arm moves from position shown in Fig. 16 to its position in Fig. 17. During this movement the upper spring undergoes-considerable compression and its counterbalancing moment increases considerably. The upper friction sleeve is heavier than the loweririctionjsleeve to overcome this excessof pressure by the upper spring under these conditions. The coeificientof static friction of the friction sleeves is considerably greater than the coeilicient of sliding. friction. 1 This assists considerably the ease of manipulation of the'present device.

In the preferred form of the inventionshown herein, the upper spring'has a reduced free length and heavier wire ascompared with the lower Iclaim:

1-. Asupport for a movable load unit comprising in combination, a base, a tubular bracket arm pivoted on said base, a load unit disposed within said arm, a friction element slidably carried by said arm and exerting outward pressure thereon, a link connected to said base and said friction element, and a, resilient body exerting force against said friction element, said friction element and resilient body cooperating to counterbalance the weight of said load unit in all positions.

2. The support set forth in'claim l in which the friction element comprises a resilient metal sleeve. a i i 3. The support'set forthin claim 2 in which theresilientbody comprises a coil springs 4. A support for a movable load unit comprising in combination, a base, an inner tubular bracket arm pivoted to said base, a friction element slidably disposed within said arm, a link connected to said base and said friction element, a resilient body disposed within said arm and exerting an upwardly directed force upon said friction element; an outer tubular bracket arm pivoted to said inner bracket arm, a friction element slidably disposed within said outer arm, a resilient body disposed within said outer arm and exerting an upwardly directed force upon said friction element, a link connecting said last named friction element and said inner bracket arm, and a load unit carried by said outer bracket arm; said links, friction elements and resilient bodies cooperating to maintain the load unit in any adjusted position.

5. The support set forth in claim 4, in which said friction elements and said resilient bodies are disposed intermediate the ends of the respective bracket arms thereby substantially freeing the pivots of any counterbalancing pressures.

6. A support for a movable mass, comprising in combination, a base, a standard supported on said base and carrying the mass at its free end; said standard having at least two jointed parts, each part comprising a tube with a longitudinal slit, a slidable split sleeve within and in frictional contact with the interior of each tube, said sleeve having an integral lug passing through said slit, a link pivoted at one end to said lug and at the other end to an adjacent part of said standard, and a resilient body disposed within each tube exerting pressure against one end of said sleeve.

7. A support for a movable mass, comprising in combination, a base, a standard supported on said base and carrying the mass at its free end; said standard having at least two jointed parts, each part having a hollow body portion, a slidable resilient sleeve within and in frictional contact with the interior of each body portion, a link pivoted at one end to said sleve and at the other end to an adjacent part of said standard, and a coil spring disposed within said body portion and exerting resilient pressure against one end of said sleeve.

8. In combination, a base, a standard, and a swivel mounting for the standard on said base, said mounting comprising a stud fixed on said base, the stud having a circumferential groove, a two-part housing receiving one end of said standard and embracing said stud, the abutting faces of said housing having inter-engaging portions, pintles passing through said portions and holding said parts in fixed assembly, said housing having a lug entering the circumferential groove ments comprising a stud fixed to one element, a two-part housing carried by the other element and rotatably embracing said stud, the housing parts having inter-engaging portions, and pintles passingthrough said portions and holding said parts in fixed assembly, the pintles being directed generally parallel to the stud.

10. A swivel connection between a pair of elements, comprising a stud fixed on one element,

a two-part housing carried by the other element and rotatably embracing said stud, the housing parts havingtwo sets of inter-engaging portions,.

pintles passing through said portions and holding said parts in fixed assembly, and inter-engaging means carried in part by said housing and in part by said stud serving to limit relative rotation of said housing and stud and to hold the same in assembled relation, the pintles being directed generally parallel to the stud.

11. A swivel connection between two parts comprising two end elements carried by said parts and an intermediate element, one of said end elements having a conical body portion, said intermediate element having ,a conical inner surface in engagement with said conical body portion, said intermediate and last named end elements having interengaging parts for holding said elements in assembled relation, the other end element and said intermediate element being connected to provide pivotal movement therebetween about an axis vertical to the axis of rotation between the intermediate and first end elements.

12. A support for a movable mass, comprising in combination, a base, a standard supported on said base and carrying the mass at its free end; said standard having two jointed tubular arms, a slidable split friction sleeve within each arm and in frictional contact with interior of the arm, a helical spring within each arm exerting force against one end of its associated friction sleeve, a link for each arm connected at one end to its sleeve and at the other end to a part of the standard adjacent the arm, the friction sleeve in the arm furthest removed from the base exerting a greater frictional pressure than the other friction sleeve.

13. A support for a movable load unit comprising in combination, a base, an inner bracket arm pivoted to said base, an outer bracket arm pivoted to said inner bracket arm, a friction element slidably carried by each arm, a helical spring carried by each arm in engagement with its friction element, a link connecting the friction element in the inner arm to the base, and another link connecting the friction element in the outer arm to the inner arm, whereby movement of the load unit relative to the base will cause the movement of at least one friction element relative to its arm and the transmission of a sliding force to it by its spring.

14. A support for a movable load unit comprising in combination, a base, a tubular bracket arm pivoted on said base, a load unit carried by said arm, a resilient friction sleeve disposed within said tubular arm and having its outer surface in frictional engagement with the inner surface of the tubular arm, a link connecting said sleeve to said base and serving to move said sleeve axially of the arm as the arm is moved relative to the base and a helical spring disposed within said arm in engagement with said sleeve and operable 1 1 by movement of the load uni-t: to transmit: a sliding force to said sleeve.

15. A support for a movable load unitcomprising in combination, a ,base, an inner tubular arm pivoted to said base, an outer tubular arm pivoted to said inner arm, a'slidable: element. disposed Withineach arm in frictional engagement with it's wall, a helical spring disposed in, each arm. in engagement with. its slidable element, a linkeconnecting the slidable element of the inner arm to the base, and another link connecting the slidable element'of the outer arm to the first. arm, Whereby movement ofthe load. unit relative to the'base will' cause the transmission of a sliding force to at. least one slid'able element by its spring.

LEON. BOLTUCLL 12 REFERENCES CITED The following references are of record. in the file'of this patent:

UNITED STATES PATENTS Number Name Date 202,621. Wood Apr. 16,1878, 730,830 Lingle; June 9, 1903 858,819 Oliver July 2, 1907 922,204 1 Smith 1 May 18, 1909" 1,231,848 Centoiella July 3, 1917 1,382,783 Howard June 28,1921 1,963,278- Pieper June 19, 1934 2,029,532 Karcher Fem 1,: 1936 2,213,051 Rosen Aug. 27, 1910 2,395,178v Fiori -1 Feb.- 19, 1946 E'iori et aL. July- 19, 1949 

